1. Field of the Invention
The present invention relates to an electronic connecting system which may be connected with a device dedicated to display information such as an OHP (Over Head Projector) or a display for indicating a handling routine for electronic equipment like an electronic calculator or an electronic note provided with such a function.
2. Description of the Related Art
As a known representative art, the OHP projection for an electronic function calculator will be described. The inventors of the present application know two proposed techniques. The first known technique is arranged to directly mount an electronic function calculator onto an OHP device and display the calculation being done by a handling operation on the OHP large display. The second known technique is arranged to connect an electronic function calculator with a device dedicated to OHP projection through a communication cable and mount the dedicated device onto the OHP device. In this arrangement, a user handles the electronic function calculator so that the handled result may be displayed on the display section of the calculator. At a time, the display data based on the handled result is transmitted to the dedicated device through the communication cable and displayed on the display section of the dedicated device so that the display data may appear on the OHP large screen for indicating a handling explanation to the audience.
Unfortunately, however, the first known technique has a shortcoming that this technique is difficult to handle because the function calculator is required to be placed on the OHP device. As a further shortcoming, it gives a handler difficulty in seeing the handling process on the display. As another shortcoming, the handler is required to be around the OHP device.
As shortcomings of the second known technique, it needs to provide a larger number of communication lines for feeding a larger number of communication lines (parallel communication) because it feeds a display signal or its converted signal indicating the result processed by the electronic function calculator or an additional dedicated circuit (parallel signal) because it needs a longer communication time. Further, since the circuitry on the sending side is quite different from that on the receiving side, such a device dedicated to display makes the electronic function calculator itself expensive.